He said after the two cars collided, both men came out of their cars. They exchanged heated words. The man from the black car raised his hands in a defensive gesture as the man from the silver car shot him twice.

Chill said the shooter “went back to his car and got a bag from the back, then walked over and shot the man who was lying on the pavement “three more times.”

Chill said the shooter walked half a block down the street, rummaged through the bag he had retrieved from his car and withdrew a mask that he put on and ran off on foot.

Police detained a man matching the killer’s description a few blocks from the shooting. They are calling him a “person of interest.” Late Monday afternoon, witnesses were viewing photo lineups at Miami Gardens police headquarters.